Details, datasheet, quote on part number: RH5RH392B-T2

The 2B/ 3B Series are PWM Step-up DC/DC converter ICs by CMOS process. The 1A IC consists of an oscillator, a PWM control circuit, a driver transistor (Lx switch), a reference voltage unit, an error amplifier, a phase compensation circuit, resistors for voltage detection, a soft-start circuit, and an Lx switch protection circuit. A low ripple, high efficiency step-up DC/DC converter can be constructed of this 1A IC with only three external components, that is, an inductor, a diode and a capacitor. These 2B/×× 3B ICs can achieve ultra-low supply current (no load) ­TYP. 15µA ­by a newly developed PWM control circuit, equivalent to the low supply current of a VFM (chopper) Step-up DC/DC converter. Furthermore, these ICs can hold down the supply current to TYP. 2µA by stopping the operation of the oscillator when the input voltage > (the output voltage set value + the dropout voltage by the diode and the inductor). These 2B/×× 3B Series ICs are recommendable to the user who desires a low ripple PWM DC/DC converter, but cannot adopt a conventional PWM DC/DC converter because of its too large supply current. The 2B/×× 3B Series ICs use the same chip as that employed in the 1A IC and are provided with a drive pin (EXT) for an external transistor. Because of the use of the drive pin (EXT), an external transistor with a low saturation voltage can be used so that a large current can be caused to flow through the inductor and accordingly a large output current can be obtained. Therefore, these 2B/×× 3B Series ICs are recommendable to the user who need a current as large as several tens mA to several hundreds mA. The 3B IC also includes an internal chip enable circuit so that it is possible to set the standby supply current at MAX. 0.5µA. These 2B/×× 3B ICs are suitable for use with battery-powered instruments with low noise and low supply current.

Error Amp. (Error Amplifier) has a DC gain of 80dB, and Phase Comp. (Phase Compensation Circuit) provides the frequency characteristics including the 1st pole (fp=0.25Hz) and the zero point (fz=2.5kHz). Furthermore, another zero point (fz=1.0kHz) is also obtained by the resistors and a capacitor connected to the OUT pin.

In RH5RH Series, the output voltage, the driver, and the taping type for the ICs can be selected at the user's request. The selection can be made by designating the part number as shown below RH5RH ­ Part Number b c